STD 12 - 4. principal of inheritance and variation — NEET STD 11 Science — Question

Select the correct match :

(A) 1869	I. Friedrich meischer
(B) 1953	II. Watson and crick
(C) 1928	III. Griffith
(D) 1952	IV. Hershey and chase

Assertion : Mast cells in the human body release excessive amounts of inflammatory chemicals, which cause allergic reactions.

Reason : Allergens in the environment on reaching human body stimulate mast cells in certain individuals.

Which is not correct about bones?

Immune activities defence mechanism for different diseases is known as

Assertion : During fertilization only head of spermatozoa enters egg.

Reason : If several spermatozoa hit the egg at same time, all can enter the egg.

A nerve impulse will travel through a nerve fibre only if the membrane suddenly becomes more permeable to

According to Hugo de Vries, the mechanism of evaluation is

All sons of a couple are colourblind because

For the maintenance of ionic gradients across the resting membrane, the sodium -potassium pump transports